Date of Award
Summer 8-20-2023
Degree Type
Thesis
Degree Name
Master of Science (MS)
Department
Biological Science
First Advisor
Joanna Brooke, PhD
Second Advisor
Timothy Sparkes, PhD
Third Advisor
Megan Schrementi, PhD
Abstract
Stenotrophomonas maltophilia is a multidrug resistant bacterium which can cause severe infections of the respiratory tract, soft tissue, and bloodstream, and its ability to form biofilms on medical implants and devices contributes to its role as a hospital-acquired pathogen (Brooke, 2021; Flores-Treviño et al., 2019). The rise of antibiotic resistance has prompted the search for new treatments against bacteria. Bacteriophages, or phages, are a promising alternative to antibiotics because they infect and kill bacteria (Ling et al., 2022). Phage therapy has gained recent attention as a life-saving treatment for antibiotic resistant infections (Racenis et al., 2023; Schooley et al., 2017). Phage Bfi2 (Biofilm formation inhibitor 2) is a novel virus that infects S. maltophilia. This thesis characterizes Bfi2, its life cycle, its activity against biofilm, and effectiveness when combined with antibiotics. Transmission electron microscopy revealed a virus with an icosahedral head and long, flexible non-contractile tail, classifying Bfi2 as a siphovirus within the Caudoviricetes class. Bfi2 is a virulent phage that forms clear plaques on lawns of S. maltophilia, and a one-step growth curve depicted a latent period of 60 minutes and a burst size of ~33 virions/cell. The phage inhibits the formation of S. maltophilia biofilm biomass and reduces the metabolic activity of 24-hour preformed biofilms. When testing its ability to inhibit planktonic growth and biofilm formation in combination with antibiotics, the activity of Bfi2 was not enhanced with any one of the five antibiotics chosen. Further work is needed to characterize the phage, but these results demonstrate its potential for phage therapy against S. maltophilia infections.
Recommended Citation
Walther, Lydia, "Targeting S. maltophilia Biofilms with Phage Bfi2" (2023). College of Science and Health Theses and Dissertations. 563.
https://via.library.depaul.edu/csh_etd/563
SLP Collection
no
